Monday, May 30, 2016

Bugtraq: [oCERT 2016-001] Jetty path sanitization issues

Description:

Jetty is a Java HTTP (Web) server and Servlet container.

The Jetty path normalization mechanism suffers of an implementation issue

when parsing the request URLs.

The path normalization logic implemented in the PathResource class and

introduced in Jetty versions 9.3.x can be defeated by requesting malicious

URLs containing specific escaped characters.

Leveraging on this weakness, a malicious user can gain access to protected

resources (e.g. WEB-INF and META-INF folders and their contents) and defeat

application filters or other security constraints implemented in the

servlet configuration.

A workaround to mitigate the issue, using the 'rewrite' module, can

alternatively be implemented as follows:

$ java -jar ../start.jar --module=rewrite etc/backslashalias.xml

or

$ java -jar ../start.jar --add-to-startd=rewrite

$ java -jar ../start.jar etc/backslashalias.xml

Workaround file backslashalias.xml contents:

<?xml version="1.0"?>

<!DOCTYPE Configure PUBLIC "-//Jetty//Configure//EN" "http://ift.tt/1KcJX5o">

<Configure id="Rewrite" class="org.eclipse.jetty.rewrite.handler.RuleContainer">

<Call name="addRule">

<Arg>

<New class="org.eclipse.jetty.rewrite.handler.RedirectRegexRule">

<Arg>.*\\.*</Arg>

<Arg>/</Arg>

<Set name="statusCode">404</Set>

</New>

</Arg>

</Call>

</Configure>

Affected version:

Jetty >= 9.3.0, <= 9.3.8

Fixed version:

Jetty >= 9.3.9

Credit: vulnerability reported by Simon Zuckerbraun of Trend Micro Zero Day Initiative

CVE: CVE-2016-4800

Timeline:

2016-05-03: vulnerability report received

2016-05-06: contacted maintainer

2016-05-11: patch provided by maintainer

2016-05-13: assigned CVE

2016-05-18: reporter confirms patch

2016-05-20: contacted affected vendors

2016-05-30: advisory release

References:

http://ift.tt/1RFfHnp

Permalink:

http://ift.tt/1WUBeAl

--

Daniele Bianco Open Source Computer Security Incident Response Team

<danbia (at) ocert (dot) org [email concealed]> http://www.ocert.org

GPG Key 0x9544A497

GPG Key fingerprint = 88A7 43F4 F28F 1B9D 6F2D 4AC5 AE75 822E 9544 A497

[ reply ]


from SecurityFocus Vulnerabilities http://ift.tt/1U7uOIa

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.